The aim of this study was to evaluate the Strengthening Families Programme for young people aged ten to 14 and their parents (SFP 10-14) in Barnsley, a northern English city, based on the experience of facilitators and families who had participated in the programme. A mixed methods design blending both quantitative and qualitative data was used in the study carried out in two phases over a nine-month period in 2005. Quantitative data were collected through: the SFP 10-14 Parent/Caregiver Survey Questionnaire, the SFP 10-14 Young Persons' Survey Questionnaire and the Strengths and Difficulties Questionnaire. Questionnaire data were compared at the beginning of the SFP 10-14 programmes (weeks 1–2) and at the end of the programmes (week 7). In addition, two focus group meetings were held with families who had undertaken the SFP 10-14 programme; and three focus group meetings were conducted with facilitators of SFP 10-14 programmes. Once quantitative and qualitative data had been analysed separately, a synthesis of the main findings from both approaches was then completed. Following the programmes, parents reported significant changes in communication limit setting, emotional management, prosocial behaviour and drugs/alcohol use. Total difficulties scores were also significantly different pre- and post SFP 10-14 programmes. For the young people, communication, and emotional management were improved and their drugs/alcohol use was less. Their total difficulties scores were also significantly different. Qualitative evidence indicated that families who participated in the study found the SFP 10-14 useful in preventing young people's alcohol and drug use in terms of: learning more about alcohol and drugs, using knowledge and skills to reduce behaviours that might lead to alcohol and drug use and, for young people, dealing with peer pressure that might lead to drug and alcohol use. Parents/caregivers and young people reported that the SFP 10-14 had played a part in improving family functioning through strengthening the family unit. The findings from this exploratory study suggest that the SFP 10-14 may be a useful primary prevention intervention in helping to prevent drug and alcohol misuse in young people. Copyright © 2009 John Wiley & Sons, Ltd.